At hospitals across South Florida, patients are taking anti-infection efforts weeks before their knee and hip replacement surgeries.

At hospitals across South Florida, patients are preparing for knee and hip replacement surgery weeks before they arrive for their procedure — scrubbing their limbs, swabbing their noses and taking hourlong classes on infection prevention.

Why? So they don't leave the operating room worse off than they arrived.

Every year, 300,000 Americans come down with so-called surgical-site infections in the tissue and bone where an operation was performed. They are among the most common and treatment-resistant ailments contracted in a hospital setting. And older adults are particularly at risk, local doctors say, not just because they are more likely to undergo knee and hip replacements but because age brings a higher risk of complication.

But evidence-based protocols in place in many South Florida hospitals are bearing fruit.

Boca Raton Regional Hospital, for example, reported no infections from the 52 knee replacement surgeries performed in the last quarter of 2013, said Dr. Charles Posternack, the hospital's chief medical officer. In all of 2012, the hospital had eight infections from 233 knee replacements conducted.

"We are trending down," Posternack said, adding that the hospital is also seeing improvements in its hip replacement numbers.

There are still no uniformly accepted practices used industry-wide to avoid such complications, but hospitals throughout South Florida — including Boca Regional, Broward Health facilities, Holy Cross in Fort Lauderdale, Cleveland Clinic in Weston and Memorial Hospital West in Pembroke Pines — generally are following the same prophylactic measures.

They recommend that knee and hip replacement patients:

Swab their nostrils a week to 10 days before surgery to screen for staph bacteria. Studies show that up to 85 percent of staph infections contracted after surgery come from patients' own bodies, so testing for bacteria, and eliminating it when it's found, is key to prevention, local doctors say.

Bathe in a special antisepticsolution two days before surgery to reduce bacterial buildup on the skin.

Take a one-hour class, preferably with a caregiver, on what to expect from surgery, how to prevent infection, which medications will be prescribed, and other instructions to follow upon discharge.

Once they arrive in the operating room, patients have their surgical site scrubbed again with an antiseptic solution, receive a preventive dose of antibiotics, have any hair clipped — not shaved with bacteria-breeding razors — and are discharged with dressings coated in bacteria-resistant agents. All medical personnel and other visitors wash their hands with antibacterial foam provided in dispensers outside the hospital room door before entering.

"You're well-informed long before surgery about what you can do to make things go easier for you" and ensure the best outcome, said Pat Schuldenfrei, director of patient safety and clinical performance improvement at Holy Cross.

Though hospital-borne infections are a stubborn problem for the health care industry — and considered by U.S. health officials to be one of the nation's most pressing medical care concerns — surgical-site infections following knee and hip replacements are even more vexing than other surgeries.

That's because the wound sites are very large and close to the surface, and the infections tend to be "very difficult and challenging to treat," said Dr. Daniel Sheldon, section chief of orthopedic surgery at Memorial Hospital West.

The protocols, used in conjunction with what Sheldon called "other, more global anti-infection efforts" in place throughout the hospital system, are yielding definitive results in helping to beat back stubborn surgical-site infections. But of all the measures, Boca Regional's Posternack said, patient education is paramount to prevention.

"Far and away, the most important factor is educating patients. It's how well you teach them and how lucky you are in getting patients who listen and follow directions," he said. "Patients are much smarter nowadays, much more savvy, much more invested in their health care. They are a different breed, and that's helped make a difference."